By Steve Fearn & Jane Austin
The last two Newsletters have featured aspects of husbandry and habitat of the Horsfield’s Tortoise (Testudo horesfieldii). This article describes experiences of keeping this species in the northern UK (Sheffield) with particular reference to how the latest captive-care information has been applied in practice.
Delilah is a female Horsfield’s tortoise, 11cm long weighing about 355g. We bought her from a pet supplier at Easter 2000 where she was being kept in a small fish-tank type vivarium. The vendor said she was a 1-year old Hermann’s tortoise, but we confirmed her true identity as a ‘Horsfield’ by the presence of 4 claws on each foot, tubicles in the rear thighs, a small scale on the tip of the tail, colouring and relatively round, flat shape.
The indoor pen we use has an opaque plastic base/sides and clear plastic lid topped with an open metal grill. A 24-inch UV tube, 60W reflector basking lamp and ceramic heater are suspended from the grill. The UV and basking lamps are driven through 24-hour plug-in timers (about £3 from supermarkets) whilst the ceramic heater is permanently ‘on’, but thermostatically controlled. Practically, this means that the heater only comes on at night and if the temperature falls too low. The UV tube fitting was bought from a DIY shop and at about £8 was half the price of a ‘reptile lamp’ UV fitting.
We use dried, composted bark as the floor substrate as it is absorbent and easy to change. It is piled to a depth of about 10cm in the corner diagonal from the basking light and covered dry, dust free straw. Delilah uses this as her overnight pallet by choice. A few flat stones have been added for interest/climbing and there is a dish containing water which is large enough for her to soak in.
We also felt it best to provide secure outdoor accommodation in which our tortoise could be confidently left to behave naturally. Various temporary designs were tried and rejected, but when a friend conveniently decided to remove his kitchen floor we obtained a supply of wooden boards with which to construct a robust tortoise pen. The chosen location receives sunlight early in the morning and keeps it thoughout most of the day for a good part of the year. The pen is about 2m long by 1.6m wide by 30cm high. One third of the length is covered with a framed clear plastic sheet hinged to the wall of the pen. The remaining length is topped with a removable frame covered in fine wire mesh. All are held secure with metal clips. Escape by burrowing is prevented by wire mesh attached to the outside of the pen and sunk into the ground to about 30cm depth. Delilah has not attempted to burrow out, which we take as a sign of approval! Underneath the plastic ‘lid’ there are two large stones capped with a thinner flat stone to make a retreat from the sun. Being undercover, it stays very dry (even in this summers’ rain) and gives extra protection from the wind. The soil floor of the whole pen is covered with soft sand to aid drainage and minimise ground humidity. There is a mound of sand and stone in the centre for climbing and dandelion, clover and grass has been planted. A shallow tray of water is always available.
Although there is some compromise on UV transmission in parts due to the use of plastic sheeting, Delilah has identified a number of basking areas in direct sun and gains further exposure during grazing. The most remarkable behaviour to witness, although not unexpected, has been burrowing. We believe this to be helpful given the need for Horsfield’s tortoises to create microclimates and it is encouraging that she has adopted such behaviour. When the night-time temperature has been forecast to stay above 15°C, we have also left her out overnight in her burrow after which she has emerged in her own time into the morning sun.
Feeding & Growth
We looked at a number of books which gave often contradictory and spurious ‘advice’ on tortoise diet. Some listed green beans, cabbage, broccoli, carrot, tomato, milk soaked bread and even dog food as being suitable foodstuffs which show the risks in relying upon relatively old books for information. We found the Tortoise Trust website to be reassuringly up to date and used this as our guide. Needless to say that green beans are not part of the regular diet due to their high protein content and other kitchen vegetables are only given in small amounts infrequently for variation. We do not give tomato, as fruits are not recommended for Horsfields. Milk, bread and dog food are totally unsuitable.
On the warm sunny days of the summer we watched with interest as Delilah was allowed to wander around the whole garden and choose her own food. Dandelion flowers and leaves were a firm favourite and now form the core of the diet, but she also took cornflower, nemesia and annual phlox. Roughly translated, this meant that we had a tortoise which could decimate a number of favourite annual bedding plants! However, it also meant that we had options of other plants with which we could supplement the dandelion-based diet and some of these were added to the outdoor pen. She tried other plants (usually as small bite from a low leaf) and never touched them again, which we took as an indicator that they should not be included in harvested feed. Clover leaves and flowers were conveniently found in abundance in the local valley and also added to the diet.
Maximum food intake was in May, June and July with a reduction becoming apparent in August. Intake declined further, falling to almost zero in the last two weeks of September and the first two weeks of October. There has been a slight increase towards the middle of October but only to between half and two dandelion leaves at one ‘sitting’. It has sometimes been necessary to wrap these around small pieces of cucumber to tempt her to maintain nutrition until pre-hibernation fasting in November. She has been less than comfortable when placed to soak during the summer but the third week of October saw her begin to do this of her own accord in the indoor pen for up to 30 minutes at a time. Speculatively, this may be a way of maintaining hydration whilst reducing food (and therefore moisture) intake. We conclude that it is always necessary to have water available as one never knows when it will be required.
During the height of summer, her weight peaked at about 410g which may have been excessive for an 11cm Horsfield. There has been a steady decrease since, perhaps partly due to the outdoor pen providing a more natural environment and exercise. At the time of writing, her weight is about 355g and the midsummer ‘bulk’ around the shoulders has reduced. There has been relatively little growth in length, but circumference around the abdominal short axis has increased. The most noticeable growth feature is a line between the costal and marginal scutes. Interestingly, the left lateral costal-marginal junction grew first, followed by the right lateral. There has also been selective growth between the costal scutes nearest the tail which has resulted in a slight flattening of the posterior aspect of the shell. Pyramiding has not occurred and the shell has a healthy shine, with the exception of the most anterior vertebral scutes which have become scuffed due to burrowing under stones.
Other Aspects of Behaviour
Upon purchase, Delilah was extremely nervous as indicated by her tendency to urinate upon handling. Over the months she has become more used human presence and by July was confident enough to go to the food dish even as the food was being placed in the indoor pen. Urination during handling has now stopped although we try to minimise contact. The vendor claimed that she was captive bred, but the apparent early handling distress has suggested to us that she was a wild import.
As already described, activity during the hottest part of summer days was curtailed in preference to seeking shade. Peak activity was therefore during the morning and later afternoon. This was sometimes mirrored indoors by a desire to retreat to the pallet despite illumination by both UV and basking lamps. During September and October, the lighting timers have been adjusted to reduce the length of the day in accordance with Delilah’s natural reduction in eating and activity. October has seen her retire to the pallet as early as 2:00pm, sometimes to emerge again briefly but often not. The lighting timers are set at 7:30am to 4:30pm for mid-October as she is clearly ‘winding down’ for the winter and we will aim for hibernation to start in early December.
So what about the cases of the disappearing Horsfield? This happened on two occasions. The first was when we allowed Delilah to have ‘free range’ run of the garden to look for food. We took our eyes of her for a few moments and she vanished. After minutes of increasingly frantic searching, she emerged from a rocky corner quite oblivious to our mounting distress and several metres away from where we left her. We were amazed at the distance she covered in such a short time leading us to believe that we may have the fastest tortoise in the west (of Sheffield anyway).
The second occasion was more mysterious as it occurred when she was in the secure outside run. Upon a routine check on her, there was nothing short, round with shell and four legs to be seen. How could she have disappeared from such a safe environment? A clue was in the disturbed dry earth by the rocks which make up the base of the stone shelter. She had dug a burrow underneath the very shelter we had made for her to sleep in and back-filled it to seal the entrance. Our apparently AWOL tortoise had constructed her own basement residence complete with water-conserving microclimate. Nature superior to human design. The moral of these two summer stories is: tortoises can run and hide.